Someone asked me for performance numbers for the PowerPC, i.e., how efficiently can a PowerPC CPU decode certain types of multimedia via FFmpeg. So I ran my compiler benchmark script on the 5 compiler configurations currently in FATE. I did 2 runs, one with and one without AltiVec optimizations. I used the 512×224 MPEG-4 part 2 video with MP3 audio (104 minutes, ~144,000 frames). These tests were run on a 1.25 GHz PowerPC G4 (Mac Mini running Linux). The FFmpeg source code was at SVN revision 18711.
Interesting stuff: The performance trends do not parallel the chaos we have seen with x86_32 and x86_64. Instead, we see continuous improvement.
Suggestions for improvement welcome, though there don’t seem to be a lot of tunable parameters for PowerPC in gcc.